Hi, Been using PCDJ Red since 2002, through a Gigaport AG , 2 channel DJ mixer , Yamaha Power Amp and RCF speakers.
The sound is great with only a minuscule hiss when the power amp is turned up full.
However on Sunday evening my mixer started to play up ( thankfully I managed to get through the gig )
I have bought a new mixer, but to have an extra safeguard I have decided to set up the lap top to use the built in mixer with PCDJ Red.
I purchased all the necessary leads and a ground loop isolator from Maplins, but when the power amp is up full the speaker noise is horrendous.
Tried all the tips on here but to no avail, its not the mains as its still there when running on battery ?
The built in sound card is a Crystal WDM audio.
Like I say, it runs silky smooth through the gigaport and external mixer ???
Any advice would be greatly received ?

its a conspiracy to ensure that you buy a digital dubbing license.

But seriously, have you tried making sure that any bluetooth / wi-fi devices within the laptop are turned OFF

Never high quality but should be OK.

So basically you use an external soundcard but want to use the internal one as a backup?

Go into the Windows mixer when using the internal card, make sure all the channels are visible, fade down everything you don't need and then mute it. You should be left with just master volume and wave.

There isn't some other software programme controller is there that adjusts settings for this card? Some have them and use presets..disable it if so.

What does it sound like if you plug headphones in and listen?

I think i had this a long time ago - I agree. Had to turn down one of the channels on the windows 'mixer' and the problem was solved.

Thanks guys.
Tried all of your suggestions but to no avail, The noise is there through headphones too, so I guess its probably the internal sound card ?
Still... I intend to carry on as I have always done, but I guess in an emergency a pair of noisy speakers will be of little detail ?

Once again thanks for the input.

Out of interest, what happens when you totally mute the internal sound card and only run off the Gigaport into the mixer?
Also, the gigaport has a headphone socket. Is there hiss heard form there when you are running PCDJ?